This invention relates generally to an apparatus for aligning articles on a conveyor belt and particularly to the alignment of flat, lightweight inserts used in continuous web business processing machines.
Machines of the type used to process continuous web business forms frequently require that insert material in the form of letters or envelopes be deposited at specific intervals on the rapidly moving web. The inserts are usually supplied from a feed station disposed above the web and it is necessary to maintain a high degree of accurate coordination between the movement of the web and the movement of the inserts. It is also necessary to maintain accurate alignment of the inserts so that they are correctly deposited on the web, and the failure to maintain such alignment can cause disruption of the entire processing system.
Prior methods of achieving accurate alignment have generally utilized moving alignment pins which engage the rear of the conveyed articles. The problem with this method is that when flat, lightweight articles such as letterheads blanks are conveyed, the engagement of the pins with the rear of such articles tends to cause buckling and consequent misalignment thereof.
Although the use of conveyor systems having belts traveling at different speeds is not in itself new, these systems are complicated and generally provide upper and lower belt arrangements as shown, for example, in U.S. Pat. No. 1,070,759. The use of upper and lower belts having a speed differential relationship is also known for the purpose of turning articles from one position to another as disclosed more recently in U.S. Pat. No. 3,462,001.
The present conveyor system solves the problem of accurate alignment of lightweight articles in a manner not disclosed in the known prior art.